Wringer mops that utilize rollers are well known in the prior art. Typically, the known wringer mops comprise a mop head connected to the end of a handle. The mop head has a pair of parallel rows of round-shaped rollers spaced apart from one another. A draw bar or other like mechanism works in cooperation with the handle and is operatively connected at one end in a manner well known in the art to the sponge material generally located between and over the rollers. More particularly, the draw bar passes through the handle and extends within the mop head between the rollers. To wring the sponge material of water or the like, the user manipulates the draw bar in conjunction with the handle to cause the draw bar to move or pull the sponge material between the parallel rows of rotating rollers, thereby squeezing the sponge material and wringing the water therefrom.
However, existing wringer mops, also known as roller mops, do not operate to wring the sponge material completely of water. That is, current designs, such as those shown in U.S. Pat. No. 4,604,767 (FIG. 3) and U.S. Pat. No. 5,655,248 (FIG. 7B), must necessarily stop short of pulling the sponge material all of the way through the rollers because the sponge material could then easily expand or flair within the spacing beneath the rollers and the mop head and would be extremely difficult to push back out between the rollers. Thus, at least the tip of the sponge material, and notably that portion of the sponge material which most often contacts the floor and dirt thereon, is not effectively wrung out. For purposes of this application, the "tip" of the sponge material will refer to that outermost portion of the sponge material which contacts the floor during the normal course of use and would otherwise not be pulled between the opposed rollers of a round-shaped roller mop.
The rotating rollers of the wringer mops of the prior art are generally manufactured in one of two ways. The first, more preferred, method uses a preferably metal center shaft having three larger diameter preferably plastic rollers mounted in a row thereon. The mop head is attached to the preferably metal center shaft at the two spaces in between the three rollers where the shaft is exposed. The other method of manufacture involves molding a one piece roller of large diameter with smaller diameter spacings molded therein for attaching the mop head thereto. Although this second method reduces the number of parts and complexity in assembling the mop, several problems exist with molding the part. For example, the completely solid, large diameter rollers are not only more expensive to manufacture but also require much more plastic. Furthermore, because the rollers use such a large mass of plastic, the manufacturing operation involves much longer molding cycles and, sometimes, even requires additional operational steps, such as dropping the plastic parts into a chilled water bath. Notwithstanding the foregoing manufacturing problems, the parts themselves may be subject to warping which would then cause the sponge material to wring unevenly.
Coring out material on a particular side of a part to reduce its weight and cycle time is generally known in the injection molding art. However, in the case of the round-shaped rollers, it is impossible to core out any of the round-shaped rollers of the prior art since there is no way to prevent the roller from rotating completely, and therefore, a cored out area will have just as likely a chance of being presented against the sponge material as the non-cored out area. Of course, it will be appreciated that the cored out area could not be used to apply pressure to the sponge material in wringing the mop. The cored out area would also undesirably provide a reservoir for water or other liquid from the sponge material into which to be squeezed.
Wringer mops of the type described hereinabove are considered useful for cleaning surfaces such as floors, but are not considered effective for cleaning transparent surfaces such as windows and the like. To that end, many roller mops now often include an attached squeegee, scrubber or other form of wiper or pad suitable for removing cleaning fluid, stains or the like from a cleaning surface. The wiper or pad can be separately attached to the mop handle and manipulated by the user as desired, or can be attached to the rollers such that, as the sponge material is drawn between the rollers, the wiper or pad extends forward to a position suitable for use. U.S. Pat. Nos. 5,655,248 and 4,604,767 show two exemplary methods for attaching the wiper or pad to the rollers such that as the sponge material is pulled between the rollers, the wiper or pad is extended to effectively clean or wipe the surface.
Thus, the need exists for an effective means for more thoroughly wringing a roller mop, including the tip of the sponge material, while improving manufacturability and cost.